Matter is anything that occupies space and has mass. All matter is made of tiny particles called atoms and molecules. Understanding the particulate nature of matter explains physical properties, states of matter, and changes in matter.
2. States of Matter
Solid
Fixed shape and volume
Particles are closely packed and vibrate in place
Examples: Ice, wood, iron
Liquid
Fixed volume, shape changes according to container
Particles are close but can slide past each other
Examples: Water, milk, oil
Gas
No fixed shape or volume
Particles are far apart and move freely
Examples: Oxygen, nitrogen, steam
3. Characteristics of Particles of Matter
Particles are extremely small
There is space between particles
Particles are in constant motion
Particles attract each other
4. Diffusion
Definition: Movement of particles from high concentration to low concentration.
Occurs in gases and liquids but very slowly in solids.
Examples:
Perfume spreading in a room
Milk mixing in water
5. Brownian Motion
Definition: Random motion of tiny particles suspended in a liquid or gas
Observed under a microscope
Provides evidence for the particulate nature of matter
6. Expansion of Matter
Solids: Expand slightly on heating
Liquids: Expand more than solids
Gases: Expand the most; occupy entire container
Practical Examples:
Railway tracks have gaps for expansion
Mercury in thermometer rises with heat
7. Changes in State of Matter
Change
From → To
Example
Melting
Solid → Liquid
Ice → Water
Freezing
Liquid → Solid
Water → Ice
Evaporation
Liquid → Gas
Water → Steam
Condensation
Gas → Liquid
Steam → Water
Sublimation
Solid → Gas
Camphor, Iodine
Deposition
Gas → Solid
Frost formation
Melting and evaporation require heat
Condensation and freezing release heat
8. Key Terms
Term
Meaning
Matter
Anything that has mass and occupies space
Atom
Smallest particle of an element
Molecule
Smallest particle of a compound
Diffusion
Movement of particles from high to low concentration
Brownian motion
Random motion of particles suspended in liquid or gas
Melting
Solid → Liquid
Freezing
Liquid → Solid
Evaporation
Liquid → Gas
Condensation
Gas → Liquid
Sublimation
Solid → Gas
Deposition
Gas → Solid
9. Examples of Particulate Nature in Daily Life
Sugar dissolving in water → diffusion
Perfume spreading → diffusion
Ice melting → melting
Frost on cold surfaces → deposition
10. Possible Questions
Very Short Answer Questions (1–2 marks)
Define matter.
Name the three states of matter.
What is diffusion?
Give one example of sublimation.
Define Brownian motion.
Short Answer Questions (3–5 marks)
Explain characteristics of particles of matter.
Describe diffusion with an example.
Differentiate between evaporation and condensation.
Explain why gases expand more than liquids or solids.
Long Answer Questions (6–8 marks)
Explain the particulate nature of matter with examples.
Describe changes in states of matter with a neat table.
Explain Brownian motion and its significance.
Discuss practical examples of expansion of matter.
Multiple Choice Questions (MCQs)
Matter is made of: a) Atoms and molecules b) Electrons only c) Neutrons only d) Protons only Answer: a
Sublimation is: a) Solid → Liquid b) Gas → Liquid c) Solid → Gas d) Liquid → Solid Answer: c
Diffusion occurs faster in: a) Solids b) Liquids c) Gases d) Both b and c Answer: d
Fill in the Blanks
Particles of matter are in constant motion.
Evaporation is Liquid → Gas.
Freezing releases heat.
True/False Questions
Gas particles are closely packed. False
Brownian motion provides evidence for particulate nature of matter. True
Diffusion does not occur in gases. False
Match the Following
Column A
Column B
Melting
Solid → Liquid
Condensation
Gas → Liquid
Sublimation
Solid → Gas
Diffusion
High → Low concentration
Brownian motion
Random motion of suspended particles
Basic Concepts of Matter
Matter is anything that: a) Occupies space and has mass b) Produces light c) Produces sound d) Exists only in solid state Answer: a
Particles of matter are: a) Extremely large b) Extremely small c) Visible to naked eye d) Stationary only Answer: b
The smallest particle of an element is called: a) Molecule b) Atom c) Compound d) Cell Answer: b
The smallest particle of a compound is called: a) Atom b) Molecule c) Proton d) Electron Answer: b
Matter is made of: a) Atoms only b) Molecules only c) Atoms and molecules d) Energy only Answer: c
States of Matter
Solid has: a) Fixed shape and volume b) No fixed shape c) No fixed volume d) Compressible freely Answer: a
Liquid has: a) Fixed shape b) Fixed volume but no fixed shape c) Neither fixed shape nor volume d) Fixed shape and volume Answer: b
Gas has: a) Fixed shape b) Fixed volume c) Neither fixed shape nor fixed volume d) Fixed volume only Answer: c
Particles in solids: a) Vibrate in fixed positions b) Slide past each other c) Move freely d) Expand indefinitely Answer: a
Particles in liquids: a) Vibrate in fixed positions b) Slide past each other c) Move freely and fill container d) Are stationary Answer: b
Particles in gases: a) Close together b) Far apart and move freely c) Vibrate in place d) Slide past each other Answer: b
Which state of matter is most compressible? a) Solid b) Liquid c) Gas d) Plasma Answer: c
Ice melting is an example of: a) Freezing b) Melting c) Evaporation d) Condensation Answer: b
Boiling water shows: a) Melting b) Evaporation c) Condensation d) Freezing Answer: b
Condensation occurs when: a) Gas → Liquid b) Liquid → Gas c) Solid → Liquid d) Gas → Solid Answer: a
Diffusion
Diffusion is: a) Random motion of particles only b) Movement of particles from high to low concentration c) Movement of solids only d) None of these Answer: b
Diffusion occurs fastest in: a) Solids b) Liquids c) Gases d) Vacuum only Answer: c
Perfume spreading in a room is an example of: a) Evaporation b) Diffusion c) Condensation d) Sublimation Answer: b
Milk mixing in water shows: a) Condensation b) Diffusion c) Sublimation d) Freezing Answer: b
Diffusion does not occur in: a) Solids b) Liquids c) Gases d) Both b and c Answer: a
Brownian Motion
Brownian motion is: a) Random motion of suspended particles b) Movement of liquids only c) Movement of solids only d) Motion due to gravity Answer: a
Brownian motion provides evidence for: a) Atomic theory / particulate nature of matter b) Diffusion c) Evaporation d) Condensation Answer: a
Brownian motion is observed under a: a) Barometer b) Microscope c) Thermometer d) Anemometer Answer: b
Which particles show Brownian motion? a) Large solids b) Small suspended particles in liquid or gas c) Atoms d) None of these Answer: b
Brownian motion was discovered by: a) Einstein b) Robert Brown c) Dalton d) Rutherford Answer: b
Expansion of Matter
Matter expands on heating because: a) Particles attract b) Particles move faster c) Particles disappear d) Particles shrink Answer: b
Most expansion occurs in: a) Solids b) Liquids c) Gases d) Plasma Answer: c
Expansion of solids is: a) Maximum b) Moderate c) Minimum d) None Answer: c
Mercury in thermometer rises due to: a) Contraction b) Expansion c) Freezing d) Diffusion Answer: b
Railway tracks have gaps to: a) Allow movement of trains b) Allow expansion of metal c) Reduce friction d) Increase pressure Answer: b
Changes in State of Matter
Melting is: a) Solid → Gas b) Solid → Liquid c) Liquid → Gas d) Gas → Liquid Answer: b
Freezing is: a) Liquid → Solid b) Solid → Liquid c) Gas → Liquid d) Liquid → Gas Answer: a
Evaporation is: a) Solid → Liquid b) Liquid → Gas c) Gas → Liquid d) Solid → Gas Answer: b
Condensation is: a) Gas → Liquid b) Liquid → Gas c) Solid → Liquid d) Gas → Solid Answer: a
Sublimation is: a) Solid → Gas b) Gas → Solid c) Liquid → Gas d) Gas → Liquid Answer: a
Deposition is: a) Solid → Liquid b) Gas → Solid c) Liquid → Gas d) Gas → Liquid Answer: b
Frost formation is an example of: a) Evaporation b) Sublimation c) Deposition d) Melting Answer: c
Camphor disappearing in air is: a) Sublimation b) Evaporation c) Condensation d) Freezing Answer: a
Melting requires: a) Heat b) Cold c) Pressure d) Vacuum Answer: a
Freezing releases: a) Heat b) Cold c) Energy absorption d) Evaporation Answer: a
True/False
Gas particles are far apart and move freely. True
Diffusion occurs fastest in solids. False
Particles of matter are stationary. False
Condensation releases heat. True
Sublimation occurs only in liquids. False
Fill in the Blanks
Particles of matter are in constant motion.
Diffusion is movement from high to low concentration.
Freezing changes Liquid → Solid.
Sublimation is Solid → Gas.
Brownian motion provides evidence for the particulate nature of matter.